Cr ZnO * (,, 200072 ) ( 2011 6 4 ; 2011 8 24 ) ZnCl 2, CrCl 3 6H 2O, 4T Cr ZnO, X,. : Cr ZnO ZnO,, 4T Cr ZnO, (M s) 0.068 emu/g,,, 16 K. :,,, Cr ZnO PACS: 81.40.Rs, 75.50.Pp, 75.50.Tt 1 (diluted magnetic semiconductor, DMS),,, [1 3]. ZnO, 3.37 ev, 60 mev, ( GaN, ZnS ),,. 2000, Dietl [4] Sato [5], (transition metal, TM) ZnO DMS., ZnO [6 8]. Cr ZnO,. Schneider [9] Cr ZnO, Cr 6 at% 1000 C 5 K, ZnCr 2 O 4. Liu [10] Cr ZnO, Cr +3, 3 at%. Elanchezhiyan [11] Zn 1 x Cr x O(x = 0.05, 0.15, 0.30), Cr,, Cr (x = 0.15, 0.30) ZnCr 2 O 4. Hu [12] Cr Zn 1 x Cr x O (x < 0.073), Raman Cr 2 O 3, x Cr 2 O 3, (V Zn ), Cr 2.7 at%. Zhuge [13] Zn 1 x Cr x O, Satoh [14]. Chu [15] Cr ZnO, * ( : 09dz1203602), ( : 09YZ27), ( : S30107) ( : IRT0739). E-mail: liying62@shu.edu.cn c 2012 Chinese Physical Society http://wulixb.iphy.ac.cn 078106-1
, Cr 3 d O 2 p. Wang [16] Cr 2% ZnO, [17].. ZnO,. 2 2.1 ZnCl 2, NH 4 Cl, CrCl 3 6H 2 O, NH 3 H 2 O,., 2 mol/l 0.02 mol/l ZnCl 2 CrCl 3 6H 2 O,. Cr 1%. 6 ml ZnCl 2, 8ml, 6ml CrCl 3 6H 2 O, 1 h. 25 ml., 453 K, 4T, 0.033 s 1, 30 s, 4 h.,., 343 K 8h., ; Cr 3+ ( ZnCl 2 ), ZnO,. 2.2 D/max-RC X (X-ray diffraction, XRD), Cu K α, 40 kv, 100 ma, λ 0.15406 nm. JSM-6700F (field emission scanning electron microscope, FESEM) EDS. LakeShore7407 (vibrating sample magnetometer, VSM). 3 1 ZnO Cr ZnO ( ZnO, S-4T S-0T) XRD. 1(a), S-0T S-4T ZnO(JCPDS, No. 36-1451),, Cr, S-0T S-4T ZnO,,, Cr ZnO. 1(b) 2 θ 30 40 XRD, ZnO, S-0T S-4T (100), (002), (101), S-4T S-0T. Cr 3+. Cr 3+ (0.63 Å) Zn 2+ (0.74 Å), Cr 3+ ZnO, Cr 3+. XRD, 1 XRD (a) (b) 078106-2
Ô n Æ Acta Phys. Sin. Vol. 61, No. 7 (2012) 078106 ²óÀ^ e Cr3+ S,þ õ, L ²óÀ^ k ur? Cr3+ \ ZnO. ã 2 3kÃóÀ^ ^ ey9ü Cr, ZnO N SEM ãú EDS ãì. lã 2(a) Ú (b) ±wñ, S-0T òw 5K/m, Ì d Ñ G â, ²þ» 100 200 nm, Ý 600 800 nm, Ü kìày u ); S-4T K y²w 5K/m, dü ks Y)G, ²þ» 150 250 nm, Ý 1 2 µm, B u \, Ãìà y u), "à²þ» 50 100 nm. ' ã wñ, óà^ äkr? â ã2 ^, N âu ½ ). ù U du \^ 3 a, b, c UþØÓ B ) ÝØ [18], l 3 kóà^ B ) ÝwÍ \, 3Ù þ ) ÝÉ ½³, ª B Uì ½ ). óà^ e Cr, ZnO N ü K Ï Ùg äk^5, É^ ^u) =. â ã 2(c) Ú (d) S-0T Ú S-4T Cr S ¹ þ O 0.49%Ú 0.83%, ` ² ó À ^ J p Cr S, Y ², ù Ú XRD ( J. kãóà^ ^ ey9ü Cr, ZnO SEM ã ((a) S-0T; (b) S-4T) Ú EDS ãì; ((c) S-0T; (d) S-4T) «Cr, ZnO N ^5U(J. dã, óà^ e S-4T 3 (298 K) L y Ñ é Ð c ^ 5, Ù Ú ^ z r Ý (Ms ) 0.068 emu/g; Ã^ e S-0T 3 evklyñc^5, ^^5. ã3 ^ ã ã 3 æ^ Ä ^ro3 eÿá ã 4 k à ó À ^ e Y 9 Ü Cr, ZnO N ^ 9 (M -T ), d d à ^ e S-0T Øp Ý (Tc ) 288 K, ó À^ e S-4T Tc 304 K. S-4T ' S-0T Øp Ýp 16 K, `²óÀ^ Ú\ Jp Cr, ZnO N Øp Ý, k u¼ c^5, ù K cï Ù AN 078106-3
[19 21]., Cr 3+ ZnO, Cr O [15],. 0.5 T,.,,., Singhal [22], : M(H) = 2M s π tan 1 [ H Hc H c tan ( πs 2 ) ] + χh, (1) 4 (1), M s H c, S, S = M r /M s, χ. (1) S-0T 280 K (FM) (PM), 5, M s 0.0235 emu/g, S-4T M s 0.0445 emu/g., M s 2,. 4 5 S-0T 280 K 5 S-0T 280 K.., 1.3 T, 0.031 emu/g, ;, 4T Cr ZnO. Cr 3+ Cr ZnO, 16 K.. [1] Wolf S A, Awschalom D D, Buhrman R A, Daughton J M, Molnár S von, Roukes M L, Chtchelkanova A Y, Treger D M 2001 Science 294 1488 [2] Matsumoto Y, Murakami M, Shono T, Hasegawa T, Fukumura T, Kawasaki M, Ahmet P, Chikyow T, Koshihara S, Koinuma H 2001 Science 291 854 [3] Chiba D, Yamanouchi M, Matsukura F, Ohno H 2003 Science 301 943 [4] Dietl T, Ohno H, Matsukura F, Cibert J, Ferrand D 2000 Science 287 1019 [5] Sato K, Katayama-Yoshida H 2001 Jpn. J. Appl. Phys. 40 L334 [6] Liu X C, Shi E W, Song L X, Zhang H W, Chen Z Z 2006 Acta Phys. Sin. 55 2557 (in Chinese) [,,,, 2006 55 2557] [7] Yang J J, Fang Q Q, Wang B M, Wang C P, Zhou J, Li Y, Liu Y M, Lü Q R 2007 Acta Phys. Sin. 56 1116 (in Chinese) [,,,,,,, 2007 56 1116] [8] Yu Z, Li X, Long X, Cheng X W, Wang J Y, Liu Y, Cao M S, Wang F C 2008 Acta Phys. Sin. 57 4539 (in Chinese) [,,,,,,, 2008 57 4539] [9] Schneider L, Zaitsev S V, Jin W, Kompch A, Winterer M, Acet M, Bacher G 2009 Nanotechnology 20 135604 [10] J, Liu X Y, Yang Y T, Wei M B 2009 J. Alloy. Compd. 486 835 [11] Elanchezhiyan J, Bhuvana K P, Gopalakrishnan N, Shin B C, Lee W J, Balasubramanian T 2009 J. Alloy. Compd. 478 45 078106-4
[12] Hu Y M, Hsu C W, Wang C Y, Lee S S, Wang S J, Han T C, Chou W Y 2009 Scripta Mater. 61 1028 [13] Zhuge L J, Wu X M, Wu Z F, Chen X M, Meng Y D 2009 Scripta Mater. 60 214 [14] Satoh I, Kobayashi T 2003 Appl. Surf. Sci. 216 603 [15] Chu D W, Zeng Y P, Jiang D L 2007 Solid State Commun. 143 308 [16] Wang B Q, Iqbal J, Shan X D, Huang G W, Fu H G, Yu R H, Yu D P 2009 Mater. Chem. Phys. 113 103 [17] Miao H Y, Li H Q, Tan G Q, An B J, Wei Y X 2008 J. Inorg. Mater. 23 673 (in Chinese) [,,,, 2008 23 673] [18] Chu D W, Zeng Y P, Jiang D L 2007 J. Phys. Chem. C 111 5893 [19] Li Y B, Li Y, Zhu M Y, Yang T, Huang J, Jin H M, Hu Y M 2010 Solid State Commun. 150 751 [20] Huang J, Zhu M Y, Li Y, Yang T, Li Y B, Jin H M, Hu Y M 2010 J. Nanosci. Nanotechno. 10 7303 [21] Yang T, Li Y, Zhu M Y, Li Y B, Huang J, Jin H M, Hu Y M 2010 Mater. Sci. Eng. B 170 129 [22] Singhal R K, Dhawan M S, Gaur S K, Dolia S N, Kumar S, Shripathi T, Deshpande U P, Xing Y T, Saitovitch E, Garg K B 2009 J. Alloy. Compd. 477 379 Synthesis of Cr-doped ZnO diluted magnetic semiconductor by hydrothermal method under pulsed magnetic field Zhu Ming-Yuan Liu Cong Bo Wei-Qiang Shu Jia-Wu Hu Ye-Min Jin Hong-Ming Wang Shi-Wei Li Ying ( Laboratory for Microstructures/School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China ) ( Received 4 June 2011; revised manuscript received 24 August 2011 ) Abstract In this study, zinc chloride, chromic chloride, ammonium hydroxide and ammonium chloride are used as the source materials to prepare the crystalline Cr-doped ZnO diluted magnetic semiconductor by the hydrothermal method under a 4-T pulsed magnetic field. The structures and the morphologies of the samples are characterized by X-ray diffraction and scanning electron microscope. The magnetic analysis of the specimens is performed by vibrating sample magnetometer. The effects of pulsed magnetic field on the microstructure and the magnetic properties of the Cr-doped ZnO are discussed. The result indicates that all the samples still have hexagonal wurtzite structures. The pulsed magnetic field is conducive to promote the crystal growth orientation. The sample fabricated under pulsed magnetic field exhibits good room temperature ferromagnetism. The saturation magnetization is 0.068 emu/g. However, the sample synthesized without magnetic field shows paramagnetism at room temperature. The Curie temperature (T c) of the Cr-doped ZnO is increased by 16 K through the pulsed magnetic field processing. Keywords: pulsed magnetic field, hydrothermal, Cr-doped ZnO, diluted magnetic semiconductor PACS: 81.40.Rs, 75.50.Pp, 75.50.Tt * Project supported by the Shanghai Science and Technology Commission (Grant No. 09dz1203602), the Shanghai Education Commissions (Grant No. 09YZ27), the Shanghai Leading Academic Discipline Project (Grant No. S30107), the Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0739). E-mail: liying62@shu.edu.cn 078106-5